Both the first and last one
False, because sometimes you already know the plot.
Answer:
The valley of ashes between West Egg and New York City consists of a long stretch of desolate land created by the dumping of industrial ashes. It represents the moral and social decay that results from the uninhibited pursuit of wealth, as the rich indulge themselves with regard for nothing but their own pleasure. The valley of ashes also symbolizes the plight of the poor, like George Wilson, who live among the dirty ashes and lose their vitality as a result.
Humanity's early fire-starting tools may have been dangerous because in the text is says,<span> "It could be lighted only by hard rubbing, and it sputtered and threw fire in all directions." This is dangerous because it would spew fire in all directions and if you think about it, the fire would hit something and then that thing would catch on fire. Lets say you were using the match inside your house. When you strike the match, a spark flies onto the wood floor and your house goes up in flames and you are stuck inside the house with no exit or escape. This may or may not happen, but because of the fire not being contained, there was a chance that you would be harmed.</span>